SOLab product specification

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Revision as of 09:50, 14 June 2013

Current document describes the format of the new product. Please also refer to the short summary of the CF convention prepared from the original source CF convention.

Contents

Product design

Given:

lat, lon, time, 6 parameters: Q – water vapor, W – cloud liquid, Vhf – wind speed (high frequency algorithm), Vlf – wind speed (low frequency algorithm), T – temperature, tau - atmospheric absorption at 10.65 GHz. This is for one swath, and we have 14 ascending and 14 descending swaths per day. Time is for a scan, pixels in scan are always 196, number of scans per swath is about 2000 and this varies from swath to swath.

Product ID

SOLAB_AMSRE_L2_NN

<VENDOR_ID>_<INSTRUMENT_ID>_<PRODUCT_LEVEL>_<ALGORITHM>

Filename

There are several patterns for filename convention. For example, all ASCAT files use next convention:

<INSTRUMENT_ID>_<PRODUCT_TYPE>_<PROCESSING_LEVEL>_<SPACECRAFT_ID>_ _<SENSING_START>_<SENSING_END>_<PROCESSING_MODE>_<DISPOSITION_MODE>_<PROCESSING_ TIME>

Therefore, filename format of the developing SOLab product may use the next convention

SOLAB_AMSRE_L2_NN_yyyymmdd_nnn_i_vv.nc

  • yyyymmdd- year, month and day
  • nnn - orbit number
  • i - orbit node: A or D
  • vv - version (v1, v2...)

NetCDF structure

Header

Attribute Value
NC_GLOBAL.title This dataset contains six geophysical parameters, retrieved from Japan passive microwave radiometer Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) onboard Aqua satellite. Time span covers 6 June 2002 - 4 October 2011. Spatial coverage is global, gridding is not done: data are in swath resolution and organized by ascending and descending paths of original AMSR-E georeferencing (totally about 14 ascending and 14 descending paths). Swath pixel sampling is about 10 km, though the actual spatial resolution is lower and depends on the channels used in the retrievals. The six geophysical parameters are retrieved only over open ocean areas, not covered by ice. They are the following: total atmospheric water vapor content, total cloud liquid water content, sea surface wind speed, based on using high frequency channels, sea surface wind speed, based on using low frequency channels, sea surface temperature and total atmospheric absorption at 10.65 GHz.
NC_GLOBAL.title_short_name SOLAB_AMSRE_L2_NN
NC_GLOBAL.institution Satellite Oceanography Laboratory (SOLab) of the Russian State Hydrometeorological University
NC_GLOBAL.creator_url http://solab.rshu.ru/
NC_GLOBAL.source AMSR-E swath brightness temperature data (Level 1B), provided by Japan Aerospace Exploration Agency. The retrieval algorithms are based on numerical simulation and Neural Networks inverse retrievals.
NC_GLOBAL.history Version 1 (of 13 June 2013)
NC_GLOBAL.references http://solab.rshu.ru/project/SOLAB_AMSRE_L2_NN
NC_GLOBAL.comment Land mask is taken from the original AMSR-E data (different for different channels), optically thick atmospheres are masked basing on usage of the total atmospheric absorption at 10.65 GHz (current threshold value is 0.04). Ice masking is applied when the brightness temperature at 6.95 GHz, horizontal polarization, is greater than 130 K.

Care should be taken when using the product near the coast line: it may contain wrong values since the original AMSR-E land masking is not perfect. Sea surface temperature is considered to be not reliable when the sea surface wind speed, retrieved with lower frequency algorithm, is greater than 12 m/s.
NC_GLOBAL.Conventions CF-1.6
NC_GLOBAL.creation_date variable
NC_GLOBAL.creation_time variable

Variables

Variable Attributes
latitude
  • long_name: latitude
  • units: degrees_north
  • standard_name: latitude
longitude
  • long_name: longitude
  • units: degrees_east
  • standard_name: longitude
time
  • long_name: time
  • units: s since 1993-01-01 00:00:0.0
  • standard_name: time
atmosphere_water_vapor_content
  • long_name:
  • units: kg m-2
  • standard_name:
  • scale_factor:
  • add_offset:
  • _FillValue:
  • coordinates: latitude longitude
atmosphere_cloud_liquid_water_content
  • long_name:
  • units: kg m-2
  • standard_name:
  • scale_factor:
  • add_offset:
  • _FillValue:
  • coordinates: latitude longitude
wind_speed_hf
  • long_name: wind speed high frequency
  • units: m s-2
  • standard_name: wind speed
  • scale_factor:
  • add_offset:
  • _FillValue:
  • coordinates: latitude longitude
wind_speed_lf
  • long_name: wind speed low frequency
  • units: m s-2
  • standard_name: wind speed
  • scale_factor:
  • add_offset:
  • _FillValue:
  • coordinates: latitude longitude
sea_surface_temperature
  • long_name: sea surface temperature
  • units: degree of Celcium
  • standard_name: sea surface temperature
  • scale_factor:
  • add_offset:
  • _FillValue:
  • coordinates: latitude longitude
atmospheric_absorption_at_11GHz
  • long_name: atmospheric absorption at 11GHz
  • units:
  • standard_name:
  • scale_factor:
  • add_offset:
  • _FillValue:
  • coordinates: latitude longitude
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